The robot

The pieces

1. the body The cardboard box that holds everything else. Two flaps folded in and taped shut.
2. the head A smaller box on top, taped to the body at the neck.
3. the left arm A cardboard tube, taped to the shoulder. It doesn't bend.
4. the right arm A cardboard tube, taped to the shoulder. It doesn't bend.
5. the left leg A wooden dowel, glued into the hip. It swings from there.
6. the right leg A wooden dowel, glued into the hip. It swings from there.
7. the left foot A flat wood block glued to the bottom of the leg, so the robot stands without tipping.
8. the right foot A flat wood block glued to the bottom of the leg, so the robot stands without tipping.
9. the battery A 9 V battery, taped inside the body. It's the only power in here — build the circuit that uses it at Ohm’s law. Build it on the bench →
10. the switch The slide switch that turns the whole robot on and off. It just makes or breaks the 9 V line — build the two-switch version at Series switches. Build it on the bench →
11. the motor The motor that turns the legs, geared 1:60 down from its bare shaft. It draws about 20 mA — build it bare at Pager in your pocket. Build it on the bench →
12. the left eye The left LED eye, lit by about 20 mA through a resistor. Build the same circuit at Light the LED. Build it on the bench →
13. the right eye The right LED eye, lit by about 20 mA through a resistor. Build the same circuit at Light the LED. Build it on the bench →
14. the buzzer The buzzer that beeps when the alarm circuit closes. It needs 9 V and about 16 mA — build it at Alarm button. Build it on the bench →
15. the wires The hookup wire that ties the battery, the switch, and the eyes into one loop. About 20 mA flows through here when the switch is closed — the same loop as Light the LED. Build it on the bench →